Behavior of the North American Monsoon in cold and warm paleoclimates
Abstract
Isotopic records of past climate have great potential to clarify the response of regional temperature and precipitation to climate change. One key regional circulation that remains poorly understood is the North American Monsoon (NAM). Uncertainty about the future of this circulation remains high, despite the critical role of monsoon rain in the hydrological cycle of the North American Southwest. In this talk, we present insights into the dynamics of NAM from hydrogen isotopic records derived from long-chain leaf waxes from both cold Last Glacial Maximum climates and warm Pliocene climates. Our previous work with leaf wax dD shows that this proxy is sensitive to the seasonal balance of rainfall, or the ratio of monsoon precipitation to rainfall brought by winter storm tracks. We combine these isotopic records with diagnostic analyses of model simulations, including forward-modeling leaf wax isotope values using output from isotope-enabled models, to understand the dynamical drivers of past changes. This combination of proxy and model-based approaches provides unique insights into the behavior of southwestern rainfall in response to a variety of global forcings.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFMPP43A..02B
- Keywords:
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- 1009 Geochemical modeling;
- GEOCHEMISTRY;
- 4914 Continental climate records;
- PALEOCEANOGRAPHY;
- 4924 Geochemical tracers;
- PALEOCEANOGRAPHY;
- 4994 Instruments and techniques;
- PALEOCEANOGRAPHY